U.S. patent application number 10/588206 was filed with the patent office on 2007-01-25 for phosphor, production method thereof and light-emitting device using the phosphor.
This patent application is currently assigned to Showa Denko K,K.. Invention is credited to Kousuke Shioi.
Application Number | 20070018573 10/588206 |
Document ID | / |
Family ID | 37402268 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070018573 |
Kind Code |
A1 |
Shioi; Kousuke |
January 25, 2007 |
Phosphor, production method thereof and light-emitting device using
the phosphor
Abstract
A phosphor characterized by being represented by the formula
Eu.sub.2-XLn.sub.XM.sub.YO.sub.3(y+1), wherein 0 .ltoreq.x <2, Y
is 2 or 3, Ln represents at least one member selected from among Y,
La, and Gd, and M represents at least one member selected from the
group consisting of W and Mo. This phosphor is effectively excited
by visible light or UV radiation having a wavelength of 220 to 550
nm for a desired light emission, particularly red light emission
with a high efficiency. Therefore, the phosphor is advantageously
employed in light-emitting devices such as a light-emitting screen,
a light-emitting diode, and a fluorescent lamp.
Inventors: |
Shioi; Kousuke; (Chiba,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
Showa Denko K,K.
|
Family ID: |
37402268 |
Appl. No.: |
10/588206 |
Filed: |
February 17, 2005 |
PCT Filed: |
February 17, 2005 |
PCT NO: |
PCT/JP05/02957 |
371 Date: |
August 2, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60548166 |
Mar 1, 2004 |
|
|
|
60555416 |
Mar 23, 2004 |
|
|
|
Current U.S.
Class: |
313/512 ;
313/503 |
Current CPC
Class: |
H01L 2924/00 20130101;
H01L 2924/00014 20130101; H05B 33/14 20130101; H01L 2224/45144
20130101; C09K 11/7739 20130101; H01L 33/502 20130101; C09K 11/7789
20130101; H01L 2224/1703 20130101; C09K 11/7794 20130101; H01L
2224/48091 20130101; H01L 2224/06102 20130101; H01L 2224/16245
20130101; C09K 11/7708 20130101; H01L 2224/48091 20130101; H01L
2224/45144 20130101; H01L 2224/48247 20130101; C09K 11/7734
20130101; C09K 11/7774 20130101 |
Class at
Publication: |
313/512 ;
313/503 |
International
Class: |
H01J 1/62 20060101
H01J001/62 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2004 |
JP |
2004-040842 |
Mar 17, 2004 |
JP |
2004-075687 |
Claims
1. A phosphor characterized by being represented by the formula
Eu.sub.2-xLn.sub.xM.sub.YO.sub.3(y+1), wherein 0.ltoreq.x<2, Y
is 2 or 3, Ln represents at least one member selected from among Y,
La, and Gd, and M represents at least one member selected from the
group consisting of W and Mo.
2. A phosphor characterized by being represented by the formula
Eu.sub.2-xLn.sub.xM.sub.2O.sub.9, wherein 0.ltoreq.x<2, Ln
represents at least one member selected from among Y, La, and Gd,
and M represents at least one member selected from the group
consisting of W and Mo.
3. A phosphor characterized by being represented by the formula
Eu.sub.2-xLn.sub.xM.sub.3O.sub.12, wherein 0.ltoreq.x<2, wherein
Ln represents at least one member selected from among Y, La, and
Gd, and M represents at least one member selected from W and
Mo.
4. A phosphor as described in claim 2, wherein x in the formula
Eu.sub.2-xLn.sub.xM.sub.2O.sub.9 satisfies the condition
0.ltoreq.x.ltoreq.1.5.
5. A phosphor as described in claim 3, wherein x in the formula
Eu.sub.2-xLn.sub.xM.sub.3O.sub.12 satisfies the condition
0.ltoreq.x.ltoreq.1.8.
6. A phosphor as described in claim 1, wherein M is W.
7. A phosphor as described in claim 1, wherein Ln is Y.
8. A phosphor as described in claim 1, which has a particle size of
50 .mu.m or less.
9. A phosphor as described in claim 1, which emits red light.
10. A light-emitting device comprising a light-emitting element and
a phosphor as recited in claim 1.
11. A light-emitting device as described in claim 10, wherein the
light-emitting element is a nitride semiconductor light-emitting
element and emits light having a wavelength falling within a range
of 220 nm to 550 nm.
12. A light-emitting screen employing a phosphor as recited in
claim 1.
13. A method for producing a phosphor as recited in claim 1,
characterized in that the method comprises firing at 800 to
1,300.degree. C. a mixture containing europium oxide or a compound
forming europium oxide through heating; yttrium oxide, lanthanum
oxide, gadolinium oxide, or at least one compound forming any of
these oxides through heating; and tungsten oxide, molybdenum oxide,
or at least one compound forming any of these oxides through
heating.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is an application filed under 35 U.S.C.
.sctn.111 (a) claiming benefit pursuant to 35 U.S.C. .sctn.119 (e)
(1) of the filing date of the Provisional Application No.
60/548,166 filed on Feb. 24, 2004, and the filing date of the
Provisional Application No. 60/555,416 filed on Mar. 23, 2004,
pursuant to 35 U.S.C. .sctn.111 (b). The disclosures of these
documents are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a phosphor which can be
effectively excited by ultraviolet (hereinafter also referred to as
UV) radiation or visible light for a desired light emission, a
production method thereof, and a light-emitting device employing
the phosphor. The phosphor is particularly preferred for emission
of red light.
BACKGROUND ART
[0003] A variety of light-emitting diodes (hereinafter also
referred to as LEDs) which emit light of a different wavelength
have been developed through combination of a light-emitting element
fabricated from a semiconductor (e.g., nitride compound
semiconductor) that effectively emits UV radiation or visible light
and a phosphor which can be effectively excited by UV radiation or
visible light for a desired light emission. At present, a
blue-emitting phosphor of (Sr, Ca,
Ba).sub.10(PO.sub.4).sub.6Cl.sub.2:Eu, a green-emitting phosphor of
3 (Ba, Mg, Mn)O.8Al.sub.2O.sub.3:Eu, and a red-emitting phosphor of
Y.sub.2O.sub.2S:Eu are disclosed as phosphors which are studied for
application to the above use (see Japanese Patent Application
Laid-Open (kokai) No. 2002-203991). Various emission colors can be
attained through mixing of these phosphors of three emission types
at arbitrary proportions. In order to attain white emission, a
phosphor Y.sub.2O.sub.2S:Eu serving as a red-emitting component
must be used in a large amount, because, as compared with the other
two phosphor components, the red-emitting phosphor exhibits
considerably lower emission efficacy, which is problematic. White
emission is attainable when a good balance is established between
among red, green, and blue emission. In this connection, emission
from a green-emitting phosphor and that from a blue-emitting
phosphor must be suppressed so as to attain the balance, since the
red emission component exhibits poor emission efficacy. Therefore,
hitherto, high-luminance white light has not yet been attained from
these phosphors.
[0004] Meanwhile, a phosphor which can be excited by UV-A radiation
or near UV radiation (300 to 410 nm) for a desired light emission
is a candidate phosphor to be incorporated into a light-emitting
screen, a decorative panel formed by incorporating the phosphor
into concrete, glass, or similar material, an indirect luminaire,
etc. However, in order to fully attain the desired effect,
improvement in emission luminance of the phosphor is required.
[0005] An object of the present invention is to solve the
aforementioned problems and to provide a phosphor which is
effectively excited by UV radiation or visible light suitable for
red light emission. Another object of the invention is to provide a
light-emitting device employing the phosphor.
SUMMARY OF THE INVENTION
[0006] The present inventors have conducted extensive studies in
order to attain the aforementioned objects, and have found that a
phosphor represented by the formula
Eu.sub.2-xLn.sub.xM.sub.2O.sub.9 (0 .ltoreq.x <2, wherein Ln
represents at least one member selected from among Y, La, and Gd,
and M represents at least one member selected from W and Mo) emits
high-intensity red light when excited by UV radiation or visible
light having a wavelength of 220 to 550 nm, and also found that a
light-emitting device such as a light-emitting diode employing the
red-emitting phosphor exhibits excellent emission characteristics.
The present invention has been accomplished on the basis of these
findings.
[0007] Accordingly, the present invention is directed to the
following.
[0008] (1) A phosphor characterized by being represented by the
formula Eu.sub.2-XLn.sub.xM.sub.yO.sub.3(y+1), wherein
0.ltoreq.x<2, Y is 2 or 3, Ln represents at least one member
selected from among Y, La, and Gd, and M represents at least one
member selected from the group consisting of W and Mo.
[0009] (2) A phosphor characterized by being represented by the
formula Eu.sub.2-xLn.sub.xM.sub.2O.sub.9, wherein 0.ltoreq.x<2,
Ln represents at least one member selected from among Y, La, and
Gd, and M represents at least one member selected from the group
consisting of W and Mo.
[0010] (3) A phosphor characterized by being represented by the
formula Eu.sub.2-xLn.sub.xM.sub.3O.sub.12, wherein 0<x<2,
wherein Ln represents at least one member selected from among Y,
La, and Gd, and M represents at least one member selected from W
and Mo.
[0011] (4) A phosphor as described in (2) above, wherein x in the
formula Eu.sub.2-xLn.sub.xM.sub.2O.sub.9 satisfies the condition
0.ltoreq.x<1.5.
[0012] (5) A phosphor as described in (3) above, wherein x in the
formula Eu.sub.2-xLn.sub.xM.sub.3O.sub.12 satisfies the condition
0.ltoreq.x<1.8.
[0013] (6) A phosphor as described in any one of (1) to (5) above,
wherein M is W.
[0014] (7) A phosphor as described in any one of (1) to (6) above,
wherein Ln is Y.
[0015] (8) A phosphor as described in any one of (1) to (7) above,
which has a particle size of 50 .mu.m or less.
[0016] (9) A phosphor as described in any of (1) to (8) above,
which emits red light.
[0017] (10) A light-emitting device comprising a light-emitting
element and a phosphor as recited in any of (1) to (9) above in
combination.
[0018] (11) A light-emitting device as described in (10) above,
wherein the light-emitting element is a nitride semiconductor
light-emitting element and emits light having a wavelength falling
within a range of 220 nm to 550 nm.
[0019] (12) A light-emitting screen employing a phosphor as recited
in any of (1) to (9) above.
[0020] (13) A method for producing a phosphor as recited in any one
of (1) to (9) above, characterized in that the method comprises
firing, at 800 to 1,300.degree. C., a mixture containing europium
oxide or a compound forming europium oxide through heating; yttrium
oxide, lanthanum oxide, gadolinium oxide, or at least one compound
forming any of these oxides through heating; and tungsten oxide,
molybdenum oxide, or at least one compound forming any of these
oxides through heating.
[0021] The phosphor of the present invention is effectively excited
by visible light or UV radiation having a wavelength of 220 to 550
nm for desired light emission. Therefore, the phosphor is
advantageously employed in light-emitting devices such as a
light-emitting screen, a light-emitting diode, and a fluorescent
lamp. LEDs emitting light of various colors can be fabricated from
the phosphor of the present invention or a plurality of phosphors
including the phosphor of the present invention. In the case of a
white LED, color rendering properties and luminance can be
enhanced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a chart showing an excitation spectrum of the
phosphor produced in Example 1.
[0023] FIG. 2 is a chart showing an excitation spectrum of the
phosphor produced in Example 21.
[0024] FIG. 3 is a schematic sectional view of a light emitting
device of an example of the present invention.
[0025] FIG. 4 is a schematic sectional view of a light emitting
device of another example of the present invention.
[0026] FIG. 5 is a schematic sectional view of a white LED.
[0027] FIG. 6 is a schematic view of a light emitting screen
comprising a phosphor.
BEST MODES FIR CARRYING OUT THE INVENTION
[0028] The phosphor of the present invention is represented by the
formula Eu.sub.2-XLn.sub.XM.sub.YO.sub.3(y+1), wherein
0.ltoreq.x<2, y is 2 or 3, wherein Ln represents at least one
member selected from among Y, La, and Gd, and M represents at least
one member selected from W and Mo.
[0029] In the phosphor represented by
Eu.sub.2-xLn.sub.xM.sub.2O.sub.9, when x satisfies the condition
0.ltoreq.x.ltoreq.1.5, emission intensity can be further enhanced
and, particularly, when x satisfies the condition
0.ltoreq.x.ltoreq.1.0, remarkably high emission intensity can be
attained. In the phosphor represented by
Eu.sub.2-xLn.sub.xM.sub.3O.sub.12, when x satisfies the condition
0.ltoreq.x.ltoreq.1.8, emission intensity can be further enhanced,
and particularly when x satisfies the condition
0.ltoreq.x.ltoreq.1.5, remarkably high emission intensity can be
attained. For M in the formula
Eu.sub.2-xLn.sub.xM.sub.yO.sub.3(y+1), W is preferred.
[0030] Generally, the emission intensity of a phosphor depends on
activator concentration. The phosphor of the present invention
contains a europium ion serving as an activator. Thus, when
europium concentration is the maximum, the highest-intensity
emission can be attained.
[0031] However, concentration quenching is known to occur at a high
activator concentration for, for example, the following reasons:
(i) cross-relaxation between activators occurs via resonance
transfer, thereby consuming a portion of excitation energy; (ii)
resonance transfer between activators causes a detour of an
excitation pathway, thereby promoting quenching or transfer of
excitation to crystal surfaces or non-radiative centers; and (iii)
aggregation of activators or formation of activator pairs converts
activators to non-radiative centers or killers (fluorescence
suppressors).
[0032] In view of the foregoing, the present invention pursues the
possible broadest compositional range so as to attain
high-intensity light emission.
[0033] FIGS. 1 and 2 show excitation (with respect to emission at
614 nm) spectrums of the phosphor produced in Examples 1 and 21,
respectively. As shown these figures, the phosphor exhibits
excitation peaks within a wavelength range of 220 nm to 550 nm,
indicating that the phosphor of the present invention is
effectively excited by visible light or UV radiation having a
wavelength falling within the above range and emits red light. In
addition, as the phosphor is also effectively excited by UV
radiation of 254 nm, the phosphor can be effectively employed in a
fluorescent lamp for general use.
[0034] The phosphor of the present invention can be excited by UV-A
radiation or near UV radiation (wavelength range: 300 to 410 nm)
for a desired light emission. Therefore, the phosphor can be
incorporated into a light-emitting screen, a decorative panel
formed by incorporating the phosphor into concrete, glass, or
similar material, an indirect luminaire, etc. The decorative panel
is a product which exerts decorative effect or indirect light
effect attributed to a display effect under sunlight or light from
an ordinary fluorescent lamp and a display effect under UV-A
radiation or near UV radiation emitted from a UV lamp.
[0035] An optimum concentration of a phosphor to be dispersed in a
resin or the like is influenced by the kind of the matrix used such
as the resin, the molding temperature, the viscosity of the raw
material, the particle shape, particle size and particle size
distribution of the phosphor, and others. Thus, the concentration
of the phosphor may be selected in accordance with conditions of
use or other factors. In order to control distribution of the
phosphor with high dispersibility, the phosphor preferably has a
mean particle size of 50 .mu.m or less, more preferably 0.1 to
10.mu.m.
[0036] The phosphor of the present invention may be produced
through the following procedure. When a europium compound, an
yttrium compound, and a tungsten compound, each forming an oxide by
heating, are employed as a phosphor source, these compounds are
weighed so as to attain the proportions which meet the formula
EU.sub.2-xY.sub.xW.sub.2O.sub.9 (0 .ltoreq.x <2). The compounds
are mixed together. If required, an optional flux may be added to
the phosphor raw material. The thus-produced raw material mixture
is placed in an alumina crucible or the like and fired in the air
at 800 to 1,300.degree. C. for several hours. After cooling, the
fired product is crushed and pulverized by means of a ball mill or
a similar device, and the obtained powder is washed with water, if
required. The solid is separated from the liquid, dried, crushed,
and classified, to thereby obtain the phosphor of the present
invention.
[0037] Oxides or compounds which form the corresponding oxides by
heating are preferably employed as the phosphor raw materials.
Examples of preferred compounds include europium compounds such as
europium carbonate, europium oxide, and europium hydroxide; yttrium
compounds such as yttrium carbonate, yttrium oxide, and yttrium
hydroxide; lanthanum compounds such as lanthanum carbonate,
lanthanum oxide, and lanthanum hydroxide; gadolinium compounds such
as gadolinium carbonate, gadolinium oxide, and gadolinium
hydroxide; tungsten compounds such as tungsten oxide and tungstic
acid; and molybdenum compounds such as molybdenum oxide and
molybdic acid. Other than the above-described compounds, an
organometallic compounds containing europium, yttrium, lanthanum,
gadolinium, tungsten, or molybdenum, and other similar compounds
may be employed in a vapor phase or liquid phase process, to
thereby produce the phosphor of the present invention or a raw
material mixture. The flux is preferably an alkali metal halide, an
alkaline earth metal halide, ammonium fluoride, etc. The flux is
added in an amount of 0.01 to 1.0 part by weight based on 100 parts
by weight of the entirety of the phosphor raw material.
[0038] Since the phosphor of the present invention is effectively
excited by visible light or UV radiation having a wavelength of 220
nm to 550 nm for a desired light emission, the phosphor is
advantageously used in a fluorescent lamp. Through a combination of
the phosphor of the present invention with a light-emitting diode
which exhibits an emission peak within a wavelength range of 220 nm
to 550 nm, LEDs of various colors may be produced. For example,
through a combination of the phosphor of the present invention with
a light-emitting diode which emits UV-A radiation or near UV
radiation having a wavelength range of 220 to 410 nm, a
red-light-emitting LED can be produced.
[0039] Alternatively, through a combination of the phosphor of the
present invention with a light-emitting diode which emits visible
light having a wavelength range of 400 to 550 nm, the light emitted
from the red-emitting phosphor excited by visible light and the
visible light emitted from the light-emitting diode are mixed,
whereby LEDs that emit light of various colors can be produced.
Further alternatively, through a combination of a plurality of
phosphors including the phosphor of the present invention and the
aforementioned light-emitting diode, LEDs that emit light of
various colors can be produced. Particularly when the phosphor of
the present invention is employed in a white LED, the color
rendering properties and the luminance can be enhanced.
[0040] The light-emitting device of the present invention is a
light-emitting device such as an LED or a fluorescent lamp. The
device of the present invention will be described by taking an LED
light-emitting device as an example. The device is fabricated from
the phosphor of the present invention and, in combination, a
semiconductor light-emitting element which emits light having a
wavelength of 220 nm to 550 nm. The semiconductor light-emitting
element is produced from any of a variety of semiconductors such as
ZnSe and GaN. The light-emitting element employed in the present
invention exhibits an emission peak within a wavelength of 220 nm
to 550 nm. Thus, a gallium nitride compound semiconductor, which
effectively excites the aforementioned phosphor, is preferably
employed. The light-emitting element may be produced by forming a
nitride compound semiconductor on a substrate through MOCVD, HVPE,
or a similar technique. Preferably,
In.sub..alpha.Al.sub..beta.Ga.sub.1-.alpha.-.beta.N
(0.ltoreq..alpha., 0.ltoreq..beta., .alpha.+.beta..ltoreq.1) is
formed to serve as a light-emitting layer. The semiconductor
structure may be a homo-, hetero-, or doublehetero-structure
including an MIS junction, a PIN junction, or a pn junction. A
variety of emission wavelengths may be attained through selection
of a material for forming the semiconductor layer and the
compositional proportions of the mixed crystals. Alternatively, a
single quantum well structure or a multiple quantum well structure,
in which a semiconductor active layer is formed from a thin film
exhibiting a quantum effect, may also be employed.
[0041] The aforementioned phosphor layer to be provided on the
light-emitting element may be formed of a single layer containing
at least one phosphor, or a plurality of the layers may be stacked.
A single layer may contain a plurality of phosphors. Examples of
the mode of provision of the phosphor layer on the light-emitting
element include incorporating a phosphor into a coating material
for covering the surface of the light-emitting element;
incorporating a phosphor into a molding member; incorporating a
phosphor into a cover member for covering the molding member; and
incorporating a phosphor into a light-permeable plate disposed on
the light emission side of an LED lamp.
[0042] Alternatively, at least one species of the aforementioned
phosphors may be incorporated into the molding member provided on
the light-emitting element. In addition, a phosphor layer
containing at least one species of the aforementioned phosphors may
be provided on the outside of the light-emitting diode. Examples of
the mode of provision of the phosphor layer on the outside of the
light-emitting diode include forming a phosphor coating layer on
the outer surface of the molding member of the light-emitting
diode; and forming a molded product (e.g., a cap) in which a
phosphor is dispersed in rubber, resin, elastomer,
low-melting-point glass, etc., followed by covering the LED with
the molded product or placing a plate produced from the molded
product on the light emission side of the LED.
[0043] FIGS. 3 and 4 show light emitting devices of examples of the
present invention, which comprises a phosphor and a light emitting
diode. In FIG. 3, a semiconductor light emitting chip (LED) 3 is
mounted on a stem with a mounting lead 2 and is connected to
another lead 2 via a gold wire, and the semiconductor light
emitting chip (LED) 3 is surrounded by a transparent resin or low
melting point glass cover 5 inside of which a phosphor layer 6 is
provided. In FIG. 4, a semiconductor light emitting chip (LED) 13
is mounted on a header 11 with a mounting lead 12 and covered with
a coated phosphor layer 16 which is further covered with a resin or
low melting point glass lens 15. The semiconductor light emitting
chip (LED) 13 is connected to another lead 12 via a gold wire
14.
[0044] FIG. 5 shows an example of a white LED, in which a
semiconductor LED, comprising a stack of an electrode 24 and a
III-group nitride semiconductor layer 23, in this order, on a
sapphire substrate 22, is mounted on a mounting lead 26 and
connected to an inner lead 27 via another electrode 25, and a
phosphor layer 21 is arranged on the top of the semiconductor LED
which, as a whole, is molded in a resin 28. Thus, light emitted
from the semiconductor LED, for example, a blue light, excites the
phosphor in the phosphor layer 21 which in turn emits a modified
color light, for example, green and red lights, by which the light
emitted from the semiconductor LED and the light modified by the
phosphor layer 21 are blended to compose white light.
[0045] FIG. 6 shows an example of a light emitting screen which is
a wall 31 made of concrete, glass or other material and containing
a phosphor, by which the wall emits a predetermined light and
providing a decoration effect by the phosphor contained in the wall
being excited by illumination light or natural light 32.
EXAMPLES
[0046] Examples of the present invention will next be described.
However, needless to say, the Examples should not be construed as
limiting the invention thereto. In the following Examples, emission
spectra were measured by use of an FP-6500 (product of JASCO
corporation).
Example 1
[0047] WO.sub.3 powder (59.62 g), Eu.sub.2O.sub.3 powder (31.67 g),
and Y.sub.2O.sub.3 powder (8.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.2O.sub.9 and
having a mean particle size of 5.8 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity (relative intensity) of this sample in the
emission spectrum was found to be 100 (the same applies to the
following). The excitation spectrum of the phosphor is shown in
FIG. 1.
Example 2
[0048] WO.sub.3 powder (56.85 g) and Eu.sub.2O.sub.3 powder (43.15
g) serving as raw materials for producing a phosphor were weighed
accurately, and these powders were uniformly mixed by use of a ball
mill, thereby producing a raw material mixture. The thus-produced
raw material mixture was placed in an alumina crucible and fired at
1,200.degree. C. for six hours in the air. The thus-fired product
was sufficiently washed with pure water, so as to remove
unnecessary components that are soluble in water. Subsequently, the
washed fired product was pulverized by use of a ball mill and
classified, to thereby produce a phosphor represented by a formula
of Eu.sub.2W.sub.2O.sub.9 and having a mean particle size of 6.0
.mu.m. When the phosphor was excited at 395 nm for emission, red
emission was observed. The emission intensity of this sample in the
emission spectrum was found to be 91.3.
Example 3
[0049] WO.sub.3 powder (57.75 g), Eu.sub.2O.sub.3 powder (39.44 g),
and Y.sub.2O.sub.3 powder (2.81 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.8Y.sub.0.2W.sub.2O.sub.9 and
having a mean particle size of 5.9 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 94.7.
Example 4
[0050] WO.sub.3 powder (61.62 g), Eu.sub.2O.sub.3 powder (23.38 g),
and Y.sub.2O.sub.3 powder (15 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of EuYW.sub.2O.sub.9 and having a mean
particle size of 5.0 .mu.m. When the phosphor was excited at 395 nm
for emission, red emission was observed. The emission intensity of
this sample in the emission spectrum was found to be 93.8.
Example 5
[0051] WO.sub.3 powder (63.75 g), Eu.sub.2O.sub.3 powder (14.51 g),
and Y.sub.2O.sub.3 powder (21.73 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.0.6Y.sub.1.4W.sub.2O.sub.9 and
having a mean particle size of 5.1 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 68.3.
Example 6
[0052] WO.sub.3 powder (66.04 g), Eu.sub.2O.sub.3 powder (5.01 g),
and Y.sub.2O.sub.3 powder (28.95 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.0.2Y.sub.1.8W.sub.2O.sub.9 and
having a mean particle size of 7.0 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 38.6.
Example 7
[0053] WO.sub.3 powder (59.62 g), Eu.sub.2O.sub.3 powder (31.67 g),
and Y.sub.2O.sub.3 powder (8.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.2O.sub.9 and
having a mean particle size of 2.3 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 98.8.
Example 8
[0054] WO.sub.3 powder (59.62 g), Eu.sub.2O.sub.3 powder (31.67 g),
and Y.sub.2O.sub.3 powder (8.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for 12 hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.2O.sub.9 and
having a mean particle size of 27.6 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 92.6.
Example 9
[0055] WO.sub.3 powder (59.62 g), Eu.sub.2O.sub.3 powder (31.67 g),
and Y.sub.2O.sub.3 powder (8.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for 12 hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.2O.sub.9 and
having a mean particle size of 47.8 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 88.4.
Example 10
[0056] When the phosphor produced in Example 9 was excited at 465
nm for emission, red emission was observed. The emission intensity
of this sample in the emission spectrum was found to be 88.4.
Example 11
[0057] WO.sub.3 powder (59.62 g), Eu.sub.2O.sub.3 powder (31.67 g),
and Y.sub.2O.sub.3 powder (8.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.2O.sub.9 and
having a mean particle size of 5.8 .mu.m. When the phosphor was
excited at 256 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 94.6.
Example 12
[0058] WO.sub.3 powder (57.4 g), Eu.sub.2O.sub.3 powder (30.5 g),
and La.sub.2O.sub.3 powder (12.1 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4La.sub.0.6W.sub.2O.sub.9 and
having a mean particle size of 5.2 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 97.2.
Example 13
[0059] WO.sub.3 powder (56.63 g), Eu.sub.2O.sub.3 powder (30.09 g),
and Gd.sub.2O.sub.3 powder (13.28 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Gd.sub.0.6W.sub.2O.sub.9 and
having a mean particle size of 5.5 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 99.1.
Example 14
[0060] MoO.sub.3 powder (47.82 g), Eu.sub.2O.sub.3 powder (40.92
g), and Y.sub.2O.sub.3 powder (11.25 g) serving as raw materials
for producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,200.degree. C. for six hours
in the air. The thus-fired product was sufficiently washed with
pure water, so as to remove unnecessary components that are soluble
in water. Subsequently, the washed fired product was pulverized by
use of a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6Mo.sub.2O.sub.9 and
having a mean particle size of 5.9 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 87.6.
Comparative Example 1
[0061] WO.sub.3 powder (67.25 g) and Y.sub.2O.sub.3 powder (32.75
g) serving as raw materials for producing a phosphor were weighed
accurately, and these powders were uniformly mixed by use of a ball
mill, thereby producing a raw material mixture. The thus-produced
raw material mixture was placed in an alumina crucible and fired at
1,200.degree. C. for six hours in the air. The thus-fired product
was sufficiently washed with pure water, so as to remove
unnecessary components that are soluble in water. Subsequently, the
washed fired product was pulverized by use of a ball mill and
classified, to thereby produce a phosphor represented by a formula
of Y.sub.2W.sub.2O.sub.9 and having a mean particle size of 6.0
.mu.m. When the phosphor was excited at 395 nm for emission, the
emission intensity of this sample in the emission spectrum was
found to be 0.
Comparative Example 2
[0062] When a conventional phosphor (Y.sub.2O.sub.2S:Eu) phosphor
was excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 23.1.
Example 15
[0063] The phosphor produced in Example 1 was blended with silicone
rubber, and the mixture was molded by means of a heat press
apparatus, thereby forming a cap-shape product. The cap-shape
product was attached to the outside of a near-UV LED (emission
wavelength: 395 nm) such that the cap covers the LED. When the LED
was operated, red emission was observed. After the LED had been
lighted for 500 hours at 60.degree. C. under 90% RH conditions, no
change attributed to the phosphor was observed in the red
emission.
Example 16
[0064] The phosphor produced in Example 1,
Sr.sub.5(PO.sub.4).sub.3Cl:Eu serving as a blue-emitting phosphor,
and BaMg.sub.2Al.sub.16O.sub.27:Eu, Mn serving as a green phosphor
were blended with silicone rubber, and the mixture was mounted on a
near-UV light-emitting device (emission wavelength: 395 nm),
thereby fabricating a white LED. The emitted white light exhibited
a general color rendering index of 87.
Example 17
[0065] The phosphor produced in Example 1 and
Y.sub.3Al.sub.5O.sub.12:Ce serving as a yellow-emitting phosphor
were blended with epoxy resin, and the mixture was mounted on a
blue-light-emitting device (emission wavelength: 465 nm), thereby
fabricating a white LED. The emitted white light exhibited a
general color rendering index of 78.
Example 18
[0066] The phosphor produced in Example 1,
Sr.sub.5(PO.sub.4).sub.3Cl:Eu serving as a blue-emitting phosphor,
and BaMg.sub.2Al.sub.16O.sub.27: (Eu,Mn) serving as a
green-emitting phosphor were blended with silicone rubber, and the
mixture was mounted on a near-UV light-emitting device (emission
wavelength: 395 nm), thereby fabricating a white LED.
Y.sub.2O.sub.2S:Eu serving as a red-emitting phosphor,
Sr.sub.5(PO.sub.4).sub.3Cl:Eu serving as a blue-emitting phosphor,
and BaMg.sub.2Al.sub.16O.sub.27:(Eu,Mn) serving as a green emission
were blended with silicone rubber, and the mixture was mounted on a
near-UV light-emitting device (emission wavelength: 395 nm),
thereby fabricating another white LED. The LED containing the
phosphor of the invention emitted white light exhibiting luminance
2.1 times that obtained from the LED employing Y.sub.2O.sub.2S:Eu
serving as a red-emitting phosphor.
Example 21
[0067] WO.sub.3 powder (68.89 g), Eu.sub.2O.sub.3 powder (24.40 g),
and Y.sub.2O.sub.3 powder (6.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.3O.sub.12 and
having a mean particle size of 4.5 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity (relative intensity) of this sample in the
emission spectrum was taken as 100 (the same applies to the
following). The excitation spectrum of the phosphor is shown in
FIG. 1.
Example 22
[0068] WO.sub.3 powder (66.40 g) and Eu.sub.2O.sub.3 powder (33.60
g) serving as raw materials for producing a phosphor were weighed
accurately, and these powders were uniformly mixed by use of a ball
mill, thereby producing a raw material mixture. The thus-produced
raw material mixture was placed in an alumina crucible and fired at
1,000.degree. C. for six hours in the atmosphere. The thus-fired
product was pulverized by use of a ball mill and classified, to
thereby produce a phosphor represented by a formula of
Eu.sub.2W.sub.3O.sub.12 and having a mean particle size of 5.8
.mu.m. When the phosphor was excited at 395 nm for emission, red
emission was observed. The emission intensity of this sample in the
emission spectrum was found to be 71.
Example 23
[0069] WO.sub.3 powder (67.21 g), Eu.sub.20.sub.3 powder (30.61 g),
and Y.sub.2O.sub.3 powder (2.18 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.8Y.sub.0.2W.sub.3O.sub.12 and
having a mean particle size of 4.7 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 91.
Example 24
[0070] WO.sub.3 powder (70.66 g), Eu.sub.2O.sub.3 powder (17.87 g),
and Y.sub.2O.sub.3 powder (11.47 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of EuYW.sub.3O.sub.12 and having a mean
particle size of 5.1 .mu.m. When the phosphor was excited at 395 nm
for emission, red emission was observed. The emission intensity of
this sample in the emission spectrum was found to be 96.
Example 25
[0071] WO.sub.3 powder (72.51 g), Eu.sub.2O.sub.3 powder (11.01 g),
and Y.sub.2O.sub.3 powder (16.48 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.0.6Y.sub.1.4W.sub.3O.sub.12 and
having a mean particle size of 5.3 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 83.
Example 26
[0072] WO.sub.3 powder (74.47 g), Eu.sub.2O.sub.3 powder (3.77 g),
and Y.sub.2O.sub.3 powder (21.76 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.0.2Y.sub.1.8W.sub.3O.sub.12 and
having a mean particle size of 5.8 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 48.
Example 27
[0073] WO.sub.3 powder (66.34 g), Eu.sub.2O.sub.3 powder (30.21 g),
and Gd.sub.2O.sub.3 powder (3.46 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.8Gd.sub.0.2W.sub.3O.sub.12 and
having a mean particle size of 5.1 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 89.
Example 28
[0074] WO.sub.3 powder (66.20 g), Eu.sub.2O.sub.3 powder (23.45 g),
and Gd.sub.2O.sub.3 powder (10.35 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Gd.sub.0.6W.sub.3O.sub.12 and
having a mean particle size of 5.8 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 99.
Example 29
[0075] WO.sub.3 powder (66.07 g), Eu.sub.2O.sub.3 powder (16.71 g),
and Gd.sub.2O.sub.3 powder (17.21 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of EuGdW.sub.3O.sub.12 and having a mean
particle size of 5.5 .mu.m. When the phosphor was excited at 395 nm
for emission, red emission was observed. The emission intensity of
this sample in the emission spectrum was found to be 96.
Example 30
[0076] WO.sub.3 powder (65.94 g), Eu.sub.2O.sub.3 powder (10.01 g),
and Gd.sub.2O.sub.3 powder (24.06 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.0.6Gd.sub.1.4W.sub.3O.sub.12 and
having a mean particle size of 5.5 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 83.
Example 31
[0077] WO.sub.3 powder (65.80 g), Eu.sub.2O.sub.3 powder (3.33 g),
and Gd.sub.2O.sub.3 powder (30.87 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.0.2Gd.sub.1.8W.sub.3O.sub.12 and
having a mean particle size of 5.8 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 53.
Example 32
[0078] WO.sub.3 powder (67.58 g), Eu.sub.2O.sub.3 powder (10.26 g),
and La.sub.2O.sub.3 powder (22.16 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.0.6La.sub.1.4W.sub.3O.sub.12 and
having a mean particle size of 5.8 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 79.
Example 33
[0079] MoO.sub.3 powder (57.89 g), Eu.sub.2O.sub.3 powder (33.03
g), and Y.sub.2O.sub.3 powder (9.08 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.l.4Y.sub.0.6Mo.sub.3O.sub.12 and
having a mean particle size of 4.7 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 88.4.
Example 34
[0080] WO.sub.3 powder (68.89 g), Eu.sub.2O.sub.3 powder (24.40 g),
and Y.sub.2O.sub.3 powder (6.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.3O.sub.12 and
having a mean particle size of 2.4 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 97.
Example 35
[0081] WO.sub.3 powder (68.89 g), Eu.sub.2O.sub.3 powder (24.40 g),
and Y.sub.2O.sub.3 powder (6.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.3O.sub.12 and
having a mean particle size of 27.8 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 91.
Example 36
[0082] WO.sub.3 powder (68.89 g), Eu.sub.2O.sub.3 powder (24.40 g),
and Y.sub.2O.sub.3 powder (6.71 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4Y.sub.0.6W.sub.3O.sub.12 and
having a mean particle size of 41.4 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 87.
Example 37
[0083] WO.sub.3 powder (66.57 g), Eu.sub.2O.sub.3 powder (30.31 g),
and La.sub.2O.sub.3 powder (3.12 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.8La.sub.0.2W.sub.3O.sub.12 and
having a mean particle size of 5.6 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 73.
Example 38
[0084] WO.sub.3 powder (66.90 g), Eu.sub.2O.sub.3 powder (23.70 g),
and La.sub.2O.sub.3 powder (9.40 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.1.4La.sub.0.6W.sub.3O.sub.12 and
having a mean particle size of 5.5 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 81.
Example 39
[0085] WO.sub.3 powder (67.24 g), Eu.sub.2O.sub.3 powder (17.01 g),
and La.sub.2O.sub.3 powder (15.75 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of EuLaW.sub.3O.sub.12 and having a mean
particle size of 5.9 .mu.m. When the phosphor was excited at 395 nm
for emission, red emission was observed. The emission intensity of
this sample in the emission spectrum was found to be 87.
Example 40
[0086] WO.sub.3 powder (67.93 g), Eu.sub.2O.sub.3 powder (3.44 g),
and La.sub.2O.sub.3 powder (28.64 g) serving as raw materials for
producing a phosphor were weighed accurately, and these powders
were uniformly mixed by use of a ball mill, thereby producing a raw
material mixture. The thus-produced raw material mixture was placed
in an alumina crucible and fired at 1,000.degree. C. for six hours
in the atmosphere. The thus-fired product was pulverized by use of
a ball mill and classified, to thereby produce a phosphor
represented by a formula of Eu.sub.0.2La.sub.1.8W.sub.3O.sub.12 and
having a mean particle size of 5.8 .mu.m. When the phosphor was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 45.
Example 41
[0087] When the phosphor produced in Example 21 was excited at 465
nm for emission, red emission was observed. The emission intensity
of this sample in the emission spectrum was found to be 86.1.
Example 42
[0088] When the phosphor produced in Example 21 was excited at 256
nm for emission, red emission was observed. The emission intensity
of this sample in the emission spectrum was found to be 98.
Comparative Example 11
[0089] WO.sub.3 powder (75.49 g) and Y.sub.2O.sub.3 powder (24.51
g) serving as raw materials for producing a phosphor were weighed
accurately, and these powders were uniformly mixed by use of a ball
mill, thereby producing a raw material mixture. The thus-produced
raw material mixture was placed in an alumina crucible and fired at
1,000.degree. C. for six hours in the atmosphere. The thus-fired
product was pulverized by use of a ball mill and classified, to
thereby produce a phosphor represented by a formula of
Y.sub.2W.sub.3O.sub.12 and having a mean particle size of 6.2
.mu.m. When the phosphor was excited at 395 nm for emission, the
emission intensity of this sample in the emission spectrum was
found to be 0.
Comparative Example 12
[0090] When a conventional phosphor (Y.sub.2O.sub.2S:Eu) was
excited at 395 nm for emission, red emission was observed. The
emission intensity of this sample in the emission spectrum was
found to be 18.2.
Example 43
[0091] The phosphor produced in Example 21 was blended in an amount
of 20 mass % with silicone rubber, and the mixture was molded by
means of a heat press apparatus, thereby forming a cap-shape
product. The cap-shape product was attached to the outside of a
near-UV LED (emission wavelength: 395 nm) such that the cap covers
the LED. When the LED was operated, red emission was observed.
After the LED had been lighted for 500 hours at 60.degree. C. under
90% RH conditions, no change attributed to the phosphor was
observed in the red emission.
Example 44
[0092] The phosphor produced in Example 21,
Sr.sub.5(PO.sub.4).sub.3Cl:Eu serving as a blue-emitting phosphor,
and BaMg.sub.2Al.sub.16O.sub.27: (Eu, Mn) serving as a
green-emitting phosphor were blended with silicone rubber in
amounts of 22.7 mass %, 3.8 mass %, and 3.4 mass %, respectively,
and the mixture was mounted on a near-UV light-emitting device
(emission wavelength: 395 nm), thereby fabricating a white LED. The
emitted white light exhibited a general color rendering index of
89.
Example 45
[0093] The phosphor produced in Example 21 and
Y.sub.3Al.sub.5O.sub.12:Ce serving as a yellow-emitting phosphor
were blended with epoxy resin in amounts of 8.8 mass% and 17.6 mass
%, respectively, and the mixture was mounted on a
blue-light-emitting device (emission wavelength: 465 nm), thereby
fabricating a white LED. The emitted white light exhibited a
general color rendering index of 81.
Example 46
[0094] The phosphor produced in Example 21,
Sr.sub.5(PO.sub.4).sub.3Cl:Eu serving as a blue-emitting phosphor,
and BaMg.sub.2Al.sub.16O.sub.27: (Eu, Mn) serving as a
green-emitting phosphor were blended with silicone rubber in
amounts of 22.7 mass %, 3.8 mass %, and 3.4 mass %, respectively,
and the mixture was mounted on a near-UV light-emitting device
(emission wavelength: 395 nm), thereby fabricating a white LED.
Y.sub.2O.sub.2S:Eu serving as a red-emitting phosphor,
Sr.sub.5(PO.sub.4).sub.3Cl:Eu serving as a blue-emitting phosphor,
and BaMg.sub.2Al.sub.16O.sub.27: (Eu,Mn) serving as a
green-emitting phosphor were blended with silicone rubber in
amounts of 45.8 mass %, 3.8 mass %, and 3.4 mass %, respectively,
and the mixture was mounted on a near-UV light-emitting device
(emission wavelength: 395 nm), thereby fabricating another white
LED. The LED containing the phosphor of the invention emitted white
light exhibiting luminance 2.7 times that obtained from the LED
employing Y.sub.2O.sub.2S:Eu serving as a red-emitting
phosphor.
INDUSTRIAL APPLICABILITY
[0095] The phosphor of the present invention can be employed in a
light-emitting screen, a decorative panel formed by incorporating
the phosphor into concrete, glass, or similar material, an indirect
luminaire, etc. The phosphor of the invention can be effectively
used in light-emitting devices such as a light-emitting diode and a
fluorescent lamp.
* * * * *